High BMI linked to lower survival

A study of almost 900,000 people has found that obesity can shorten life and that BMI is a good predictor of overall mortality

A study investigating the relationship between lifespan and body-mass index (BMI) in almost 900,000 people has found that obesity can shorten life and that BMI is a good predictor of overall mortality. The research found that the most obese faced a reduction in life of between eight and 10 years – the same as the reduction faced by smokers.

The results were taken from collaborative analysis of 57 studies of baseline BMI versus mortality over several years in participants mostly from western Europe and North America. A total of 61 per cent of subjects were male and with an average recruitment age of 46 and a mean BMI of 25kg/m2.

The researchers found that though other anthropometric measures, such as waist circumference and waist-to-hip ratio, could well add extra information to BMI, and BMI to them, BMI itself was a strong predictor of overall mortality both above and below the apparent optimum of about 22.5-25 kg/m2. The progressive excess mortality found above this range was due mainly to vascular disease. At 30-35kg/m2, median survival was reduced by two to four years, while at 40-45kg/m2, it was reduced by eight to 10 years, which was comparable with the effects of smoking.

Funding for the study, Body-mass index and cause-specific mortality in 900 000 adults: collaborative analyses of 57 prospective studies, came from the UK Medical Research Council, British Heart Foundation, Cancer Research UK, EU BIOMED programme, US National Institute on Aging, and Clinical Trial Service Unit (Oxford, UK).